Converting Garbage into Fuel

Waste gasification, a process for converting garbage into fuel and electricity without incinerating it, may be a step closer to large-scale commercialization. Last week, Houston’s Waste Management, a major garbage-collection and -disposal company, announced a joint venture with InEnTec, a startup based in Richland, WA, to commercialize InEnTec’s plasma-gasification technology.

Garbage disposal: This demonstration plant can process 25 tons of waste a day using technology developed by the startup InEnTec.

Waste Management will fund the new venture, which will be called S4 Energy Solutions, as well as provide infrastructure and expertise from its waste-collecting and -processing businesses to make the technology economical. The company, which will operate and market plasma-gasification technologies, will be announcing specific projects to build facilities later this year. The involvement of Waste Management could signal that the technology, which has been more expensive than other waste-disposal options, is finally reaching a stage at which it can be practical. “Up until late last year, it was under the radar,” says James Childress, the executive director of the Gasification Technologies Council. “Now the big players are finally getting involved in this.”

InEnTec’s technology, originally developed at MIT and the Pacific Northwest National Laboratory, in Richland, WA, uses a multiple high-temperature processes–including subjecting garbage to plasma arcs–to break down organic materials into syngas, a mixture of hydrogen and carbon monoxide. Syngas can either be directly burned in gas turbines to produce electricity, or it can be converted into other fuels, including gasoline and ethanol. Metals and other inorganic materials in garbage can be isolated and recycled. The combination of high temperatures and an oxygen-poor environment that prevents the garbage from catching fire eliminates the production of dioxins and furans, two toxic chemicals produced during incineration.

That core technology has been proved, says Joseph Vaillancourt, managing director at Waste Management and the senior vice president of the new joint venture. What’s kept it from being commercialized, he says, is the need to develop the processes for economically collecting and feeding waste into the system, and on the “back end” pairing the syngas produced with gas turbines for generating electricity, or other chemical processes for converting it into fuels. Vaillancourt says that Waste Management has already developed infrastructure for collecting and processing waste and for using heat from incinerators for generating electricity, and it will employ its “knowledge and wherewithal” to develop an “integrated system” using InEnTec’s technology.

S4 Energy Solutions plans to market the first gasification units in specialized markets such as those concerned with the disposal of automobile shredder residue or medical waste, for which landfills often aren’t an option, hence companies are willing to pay more to dispose of waste. Eventually, they could be used more generally for municipal solid waste, especially in rural towns and small cities that do not produce enough waste for cheaper incinerator technologies to be practical. The technology has the benefit of allowing customers to generate some of their own electricity, which could make it more affordable.

There may still be hurdles to commercial success. Childress notes that waste gasification may still face problems with local regulations. And companies using similar technologies have failed in the past. Nevertheless, some waste-gasification companies are reporting initial success. For example, Enerkem, based in Edmonton, Alberta, has opened a commercial facility to convert used utility poles into methanol and ethanol. It has signed an agreement with the city of Edmonton to process 100,000 tons of municipal solid waste a year for 25 years, although that’s still a relatively small amount compared with other options for disposing of waste.

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My reporting as MIT Technology Review’s senior editor for materials has taken me, among other places, to the oil-rich deserts of the Middle East and to China, where mountains are being carved away to build the looming cities.… More

Growing up, I lived for a time in the Philippines, where I knew people who lit their tiny homes with single lantern batteries or struggled to breathe through the dense diesel fumes of Manila, so I have a feel for the pressing need around the world for both cheap energy and clean energy.